Comparison of Sequential Treatment With Androgen Receptor-Targeted Agent Followed by Another Androgen Receptor-Targeted Agent Versus Androgen Receptor-Targeted Agent Followed by Docetaxel in Chemotherapy-Naive Patients With Metastatic Castration-Resistant Prostate Cancer.

BACKGROUND: An important clinical question of great interest to clinicians is how to best sequence androgen receptor targeted agents (ARTAs) and chemotherapy for metastatic castration-resistant prostate cancer (mCRPC), but the answer is still unclear.

MATERIALS AND METHODS: To evaluate and compare the clinical outcomes of ARTA and docetaxel (DTX) as second-line treatment in the post first-line ARTA, we conducted a retrospective analysis of chemotherapy-naive mCRPC patients who had received sequential treatment with ARTA followed by another ARTA (ARTA-ARTA) or ARTA followed by DTX (ARTA-DTX).

RESULTS: A total of 97 patients were treated with the ARTA-ARTA sequence and 42 with the ARTA-DTX sequence. A prostate-specific antigen (PSA) response to the second-line treatment was observed in 18.6% in the ARTA-ARTA and in 33.3% in the ARTA-DTX sequence, but the difference in PSA response was not statistically significant (P = .057). The median progression-free survival (PFS) was significantly different between ARTA and DTX in the second-line treatment (hazard ratio [HR], 0.38; 95% confidence interval [CI], 0.24-0.59; P < .001). The favorable outcome in the ARTA-DTX sequence compared with the ARTA-ARTA sequence remained (HR, 0.51, 95% CI, 0.33-0.80; P = .004) in the combined PFS (first-line PFS + second-line PFS). However, no statistically significant difference in overall survival (OS) between the 2 groups was observed (HR, 0.60; 95% CI, 0.34-1.09; P = .095). In multivariate analysis, the ARTA-DTX sequence was identified as an independent prognostic factor for combined PFS, but not OS.

CONCLUSION: ARTA-DTX might improve clinical outcomes in terms of second-line PFS and combined PFS, compared with the ARTA-ARTA sequence. However, this significance was not observed for OS.